Wallflowers flounce their charms
Colourful and fragrant, wallflowers fill borders with their audacious presence in springtime
ASEA OF FRAGRANT, bright yellow wallflowers, their petals the colour of egg yolk, rises above stately tulips on a warm spring day. It is a view that gladdens the heart. Unashamedly vibrant and blowsy, the simple blooms of the wallflower are neither sophisticated nor delicate, but their four broad petals ooze colour as they flutter gently in the breeze. They are so enchantingly scented and inextricably linked to gardens of the past that these plants never fail to please.
Wallflowers are brassicas: a group which also includes cabbages and cauliflowers. They are evergreen small shrubs, with narrow, green leaves arranged alternately up the stems. They have a woody base, but the shoot tips are soft. They also have rather small root systems for the size of the mature plants. Although strictly perennial shrubs, they are usually grown as biennials: sown one year to bloom the next, then discarded, although some bloom for a second year. In poor soils, the plants grow more slowly and become perennial, just as they would in their native soils, where they grow among rocks or in the mortar and scraps of soil in old walls, as their naturalised seedlings have done in Britain for centuries.
Wallflowers, or erysimum, are found wild throughout the temperate areas of the northern hemisphere, where they are usually annuals, biennials or short-lived shrubs. The common wallflower, Erysimum cheiri, is native to Europe, while the Siberian wallflower, Erysimum x marshallii, with its smaller, bright orange flowers, is found further east. Most wallflowers have yellow or orange flowers in the wild, but in the south of Europe and the Canary Islands, species such as E. linifolium and E. scoparium have purple and lilac flowers, often
accompanied by grey foliage and a woody habit, which is adapted to their hot, dry habitat. These characteristics have been inherited by some of their cultivated offspring, such as erysimum ‘Bowles’s Mauve’.
In the garden, wallflowers are loved for their colourful and highly fragrant flowers borne in spring. These are robust, leafy plants and are particularly useful for filling gaps in the border. Most grow to approximately 18in (46cm) when mature and in flower, and should be planted 8-10in (20-25cm) apart to knit together when in bloom. They traditionally flower from late March to early May, depending on the season and their position in the garden, blooming earlier in a sunny, sheltered location. The range of colours includes creamy yellow, bright yellow, gold, orange, scarlet, crimson, pinks and purples, and they are very popular with bees and early-flying butterflies.
Traditional wallflowers are sown in late spring to flower the following year; although the perennial types, such as ‘Bowles’s Mauve’, can be planted during any season and live for two to three years, blooming every year from March until at least June.
These plants very much suited the Victorian love of formality, when they were planted in neatly regimented beds and underplanted with tulips. Even now, they are often planted with tulips in contrasting or complementary colours. Because they are bulky and useful for filling large areas, they can be planted in clumps in the border, to be replaced by summer bedding plants. A clump of wallflowers can be
edged with other spring bedding, including forget-me-nots, bellis and winter-flowering pansies and violas, which all come into flower at the same time.
Buying and growing
To get the best from wallflowers, some planning is required. Although they bloom in spring, the seeds need to be sown almost a year earlier, from April to June. The traditional way to grow them is in the ground before transplanting them in October to their final flowering positions.
Most people buy wallflowers as plants in the autumn. Traditionally, these are ‘pulled’ from the field, bundled into bunches of 10 and wrapped in newspaper, then kept fresh in buckets or trays of water. They will often be a mix of colours. It is essential that these plants are bought when fresh, as the wrapped leaves will become yellow and a few days later will begin to develop the characteristic rotten cabbage smell. Buying wrapped plants also poses a risk: if the soil in which the plants were grown was infected with club root disease, they could bring it in with them. This is a soil-borne disease that is difficult to eradicate and affects a wide range of related brassicas, including honesty, and vegetables such as cabbage and cauliflower.
It is also common to see pots of seedlings for sale in the autumn, approximately 4in (10cm) in height and unbranched. These small plants will never make a good display and should be avoided. Once planted out in October, they need a period to recover and will not have sufficient time to branch out and become bushy. As wallflowers will not grow much in winter, it is essential that only bushy specimens are planted in autumn.
For the best results, wallflowers are definitely worth growing from seed, and no special equipment is required for these hardy plants. They are often raised in the vegetable garden because they are not particularly attractive at this stage. The seeds should be sown in late spring in a prepared, weed-free area of soil. They are sown thinly, approximately ¼in (6mm) deep, and kept well watered until the seedlings appear in two to three weeks’ time. When the plants are 3-4in (8-10cm) high, they can be transplanted to approximately 3in (8cm) apart, in rows 12in (30cm) apart. The growing tips should be pinched out as they are transplanted to encourage bushiness and also help to reduce wilting. They should be watered immediately after planting, then kept moist for a few weeks to aid establishment, especially as it is likely to be high summer at this stage. If the seeds were sown thinly and only few plants are needed, it may be possible to just thin them out in the seed rows.
By late September, the plants will be ready to put into their final position, and it is certainly best to have them
planted before November, when the cold weather sets in, so they are well established before winter. The plants are extracted from the soil using a fork or trowel, taking care not to damage the roots. It is normal for wallflowers to drop a lot of leaves after transplanting, but this can be minimised by planting as quickly after lifting as possible and watering well, especially in dry weather.
Wallflowers make a wonderful display in large pots, bringing colour and scent right up to the house in spring. Although they will grow in multipurpose compost, they perform better if some loam is added. The most practical way to do this is to mix equal parts of multipurpose compost and John Innes No 3, so there will be no need to feed them after planting. If only multipurpose compost is used, controlled-release fertiliser should either be added to the compost at planting time in autumn or the plants fed every week with a liquid fertiliser from March onwards.
Wallflowers need a sunny site and well-drained soil. They will not flower well in shade and may rot in wet soils. Their hardiness and the way they survive winter is linked to the wetness of the soil: they will struggle if their roots are waterlogged. In extreme winters, they may lose lots of leaves, but usually recover to flower in spring. Even so, a sheltered site will give best results.
When in bloom, flowering can be extended a little if the main flower stems are cut off as soon as the last blooms on the stem are fading and before the seed pods are fully developed. This will encourage side shoots to bloom.
Pests and diseases
Wallflowers are not prone to many problems, especially once in their flowering position, but aphids can attack small seedlings and cause distorted leaves. The most troublesome pest, only likely to strike when seedlings are very small, is the flea beetle: a tiny, jumping, black beetle that bites small holes in the leaves. While this is rarely a serious issue, sowing a row of radishes next to the wallflowers will divert the beetles’ attention to those instead.
The worst threat is from club root. This is a disease of all brassicas and is present in the soil. It causes the roots to swell, and plants lose vigour. If affected plants are moved to a new area, they will also infect that soil with the fungus responsible for the disease, where it will remain for many years. The fungus prefers acid soil, so liming the soil helps
“If e'er Titania wears a velvet gown, Such petals form the fabric of her dress; And when did mortal princess ever wear Robes of such texture and a hue so fair?” Robert Henry Forster, Ô Wallflowers’
to prevent it, as well as protecting any other brassicas the gardener intends to plant.
Propagation
Old wallflowers left in borders often survive for another season, although they can become straggly. Old plants frequently become infected by viral diseases, which cause streaking of the flower colour. Left to their own devices, wallflowers can self-seed in dry, sunny locations, especially in old stone walls. If plants are not pulled up immediately after flowering, the seeds can be collected, but they may not be ready to harvest until late in spring, which is too late to sow for immediate use, so they may need to be stored for sowing the following year.
In recent years, wallflowers have sadly declined in popularity, ousted by the ubiquitous winter-flowering pansy and viola. While wallflowers do have a shorter flowering display and are more work, the sheer joy they bring in spring, filling the air with their perfume and the garden with their bright colour, is surely reason enough to plant them. Old varieties are a delightful link with the past, while new generations of hybrids promise larger flowers and a smattering of blooms in autumn and winter.
Combine all of this with their use as delightful cut flowers to mix with polyanthus and other cottage garden favourites, and it would be a shame not to continue the British love affair with the wallflower.